I am experiencing this same issue. I'm not trying to add to a specific store, but saving it via the model's configured proxy which is attempting an update instead of a create/insert due to the phantom flag being false.

The phantom value outputs as false and the save ends up passing the proxy an update operation which fails for me because the backend I'm using doesn't have the record. I can work around it by setting phantom manually, but it shouldn't be necessary.

The reason we don't need that is because the logic in the constructor of Model sets phantom to true unless the Model gets a specific id in it's data. Is there any way you guys can give me some more code samples that allow me to replicate the issue? I have tried everything and am not able to create a model that is not phantom if I don't pass in an id to the constructor or in the data.

Alright, thanks for the examples again. I'm gonna try and dive into this one again. I just realized this might have something to do with a defaultValue being set on an id field. I'm gonna investigate and get back to you guys.